In order to allow high speed rotation of a rotating anode, precise balancing of the rotating portion is needed. Thus, for example, unwanted vibration caused by an off-balance is avoided. For example, after the assembly of an anode rotating system, material is removed for balancing purposes, for example by drilling, milling or grinding. However, this requires particular attention in terms of cleaning, in order to prevent any material dust inside the vacuum housing into which the balanced anode assembly is then mounted. Further, a need for balancing, so-to-speak re-balancing, may also arise up after the rotating anode system is mounted into an X-ray tube. Since the rotating parts are enclosed in vacuum tight tube frames, no further balancing is possible. WO 2011/039662 A1 describes balancing of the rotary anode of an X-ray tube in which the anode comprises one or more balancing cavities partly filled with balancing material being solid at a operating temperature of the X-ray tube and liquid at a higher temperature to adjust the centre of gravity of the anode even in tubes which have already been used and where the imbalance, for example, is a result of such use. However, it has been shown that the steps of heating up the balancing material, dislocating the balancing material such that imbalance of the anode is compensated, and the cooling of the balancing material requires relatively complex measurements.